How can I model the crevasses in this low-poly sphere?
The Cell Fracture add-on would be a good start.
(The Cell Fracture add-on comes with Blender, all you have to do, is activating it via Menu -&gt; Edit -&gt; Preferences -&gt; Add-ons)

Create a sphere (icosphere or rounded cube work best) with a decent polycount.



Initiate Cell Fracture via F3 - Search - Cell Fracture.
In the settings dialog under &quot;Own Particles&quot; - &quot;Point Source&quot;,
change the Source Limit to 50 and under &quot;Recursive Shatter&quot;, change
the Recursive Subdivision to &quot;Big&quot; and hit &quot;OK&quot;.




Hide the original sphere, then select all objects with &quot;_cell&quot; in
their names.
Go to the &quot;Transform Options&quot; dropdown menu and check &quot;Locations&quot;.
This will provide us with the option to &quot;explode&quot; the individual
objects away from their origins, which in our case is the center of
the original sphere.




Hit S and scale the selected objects, until the desired
gap size is reached.



You can then unhide the original sphere and proceed from there with
additional modifications (decimate, boolean, etc)